Philip Stephens

Publications (2)0 Total impact

• Source

  Available from: ArXiv

  Article: Status of Eikonal Two-Loop Calculations with Massive Quarks

  Nikolaos Kidonakis, Philip Stephens
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  ABSTRACT: We present results for two-loop diagrams with massive quarks in the eikonal approximation. Explicit expressions are given for the UV poles in dimensional regularization of several of the required integrals.
  06/2008;
• Source

  Available from: ArXiv

  Article: Resummations in QCD hard-scattering at large and small x

  Nikolaos Kidonakis, Agustin Sabio Vera, Philip Stephens
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  ABSTRACT: We discuss different resummations of large logarithms that arise in hard-scattering cross sections of quarks and gluons in regions of large and small x. The large-x logarithms are typically dominant near threshold for the production of a specified final state. These soft and collinear gluon corrections produce large enhancements of the cross section for many processes, notably top quark and Higgs production, and typically the higher-order corrections reduce the factorization and renormalization scale dependence of the cross section. The small-x logarithms are dominant in the regime where the momentum transfer of the hard sub-process is much smaller than the total collision energy. These logarithms are important to describe multijet final states in deep inelastic scattering and hadron colliders, and in the study of parton distribution functions. The resummations at small and large x are linked by the eikonal approximation and are dominated by soft gluon anomalous dimensions. We will review their role in both contexts and provide some explicit calculations at one and two loops. Comment: 36 pages, 12 figures, invited contribution to the edited book "The Physics of Quarks"; Eqs. 31 and 47 corrected, references updated
  02/2008;